From: Guenter Roeck <linux@roeck-us.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
linux-kernel@vger.kernel.org, Guenter Roeck <linux@roeck-us.net>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH] scripts/kallsyms: Ignore symbol type 'n'
Date: Wed, 4 Oct 2017 09:54:23 -0700
Message-ID: <1507136063-3139-1-git-send-email-linux@roeck-us.net> (raw)
gcc on aarch64 may emit synbols of type 'n' if the kernel is built with
'-frecord-gcc-switches'. In most cases, those symbols are reported
with nm as
000000000000000e n $d
and with objdump as
0000000000000000 l d .GCC.command.line 0000000000000000 .GCC.command.line
000000000000000e l .GCC.command.line 0000000000000000 $d
Those symbols are detected in is_arm_mapping_symbol() and ignored. However,
if "--prefix-symbols=<prefix>" is configured as well, the situation is
different. For example, in efi/libstub, arm64 images are built with
'--prefix-alloc-sections=.init --prefix-symbols=__efistub_'.
In combination with '-frecord-gcc-switches', the symbols are now reported
by nm as:
000000000000000e n __efistub_$d
and by objdump as:
0000000000000000 l d .GCC.command.line 0000000000000000 .GCC.command.line
000000000000000e l .GCC.command.line 0000000000000000 __efistub_$d
Those symbols are no longer ignored and included in the base address
calculation. This results in a base address of 000000000000000e, which
in turn causes kallsyms to abort with
kallsyms failure:
relative symbol value 0xffffff900800a000 out of range in relative mode
The problem is seen in little endian arm64 builds with CONFIG_EFI enabled
and with '-frecord-gcc-switches' set in KCFLAGS.
Explicitly ignore symbols of type 'n' since those are clearly debug
symbols.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
scripts/kallsyms.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 5d554419170b..9ee9bf7fd1a2 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -158,7 +158,7 @@ static int read_symbol(FILE *in, struct sym_entry *s)
else if (str[0] == '$')
return -1;
/* exclude debugging symbols */
- else if (stype == 'N')
+ else if (stype == 'N' || stype == 'n')
return -1;
/* include the type field in the symbol name, so that it gets
--
2.7.4
next reply index
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 16:54 Guenter Roeck [this message]
2017-10-04 17:44 ` Ard Biesheuvel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1507136063-3139-1-git-send-email-linux@roeck-us.net \
--to=linux@roeck-us.net \
--cc=akpm@linux-foundation.org \
--cc=ard.biesheuvel@linaro.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
LKML Archive on lore.kernel.org
Archives are clonable:
git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
linux-kernel@vger.kernel.org
public-inbox-index lkml
Example config snippet for mirrors
Newsgroup available over NNTP:
nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git